The invention relates to a mold clamping device for an injection-molding machine.
From DE10040819A1 a 2-platen mold clamping device is known, in which for moving the movable platen a spindle drive is provided between the fixed platen and the movable platen. One end of each spindle shaft is mounted in the fixed platen and is constructed as a piston of a piston-cylinder unit which is able to be acted upon by a pressure medium. The spindle shafts therefore form at the same time the columns of the mold clamping device which are acted upon by clamping force. This is disadvantageous in so far as the spindle drive is exposed to high mechanical stresses during the build-up of clamping force.
DE10316199A1 discloses a 2-platen mold clamping device with a fixed and a movable platen, wherein an electromotive spindle drive is provided for moving the movable platen. An AC servomotor is fastened to the fixed platen, the drive shaft of which motor is coupled with a spindle shaft. The end of the drive spindle facing the AC servomotor is mounted rotatably in a bearing in the fixed platen. The end of the spindle shaft facing away from the AC servomotor is guided through a spindle nut which is connected in a torque-proof manner with the movable platen. The spindle shaft can be rotated by means of the AC servomotor. Via the spindle nut, the rotational movement of the spindle shaft is converted into a linear movement of the movable platen. Furthermore, four pressure pads are provided on the fixed platen for the generation of the clamping force. Owing to the rigid mechanical coupling of the spindle drive between the two platens, however, no injection-compression molding methods can be carried out with the pressure pads.